汶川县肖家沟泥石流物源演变及冲出规模研究  

Characteristics of Xiaojiagou debris flow source evolution and inrushing scales in Wenchuan earthquake area

作　　者：张建石 ZHANG Jianshi(North China Engineering Investigation Institute Company Limited,Shijiazhuang 050021,China;Technological Innovation Center for Mine Groundwater Safety of Hebei Province,Shijiazhuang 050021,China)

机构地区：[1]华北有色工程勘察院有限公司,河北石家庄050021 [2]河北省矿山地下水安全技术创新中心,河北石家庄050021

出　　处：《人民长江》2020年第8期37-43,共7页Yangtze River

基　　金：国家重点研发计划项目(2017YFC1501000)。

摘　　要：为研究强震区泥石流流域内物源演化特征并预测其冲出规模特征,以映秀镇肖家沟为研究对象,利用搜集到的4期高清遥感影像和DEM数据,结合ArcGIS技术对肖家沟流域内的崩滑体进行详细的解译。通过统计分析得出其震后多年间的物源演变规律及特征。结果表明:未来3~5 a间,在没有强降雨等外力作用的条件下,肖家沟的物源状态会持续呈现衰减趋势,并最终达到稳定状态。但现场调查表明:现阶段沟内仍存有大量沟道物源及少量崩滑物源,而且该沟的地貌在地震、山洪、泥石流的下切冲蚀作用下,更有利于水动力条件的形成,进而诱发物源的起动,这也在一定程度上降低了泥石流暴发的临界雨强,因此在持续性强降雨的作用下仍有暴发泥石流的可能性,仍需要加强泥石流的预警、防治及活动性预测等研究工作。运用FLO-2D软件模拟不同频率条件下的泥石流的冲出特征,结果显示:在5%,2%的降雨频率条件下,肖家沟泥石流将造成河流的部分淤塞,但均不会造成堵江,而在1%的降雨频率的条件下将造成堵江。In order to study the source evolution and inrushing scales of Xiaojiagou debris flow in Wenchuan earthquake area,using 4 high-definition remote sensing images and DEM data,and combining with ArcGIS technology,we interpreted slumped mass in Xiaojiagou watershed in detail.The results show that in the next 3~5 years,if without heavy rainfall and other external forces,the source state of Xiaojiagou will continue to decay and eventually reach a stable state.The field investigation shows that there are still a large number of channel-type sources and a small amount of landslide sources in the gully at present,and the geomorphology of the gully is also conducive to the formation of hydrodynamic conditions under the action of earthquake,mountain floods and debris flow,which induces the sliding of the source,thus reducing the critical rainfall threshold of the debris flow.Therefore,there is still the possibility of debris flow under the action of persistent heavy rainfall,and it is still necessary to strengthen the early warning,prevention and activity prediction of debris flow.We use FLO-2D software to simulate the inrushing characteristics of debris flow under different frequency conditions.The results show that under the condition of rainfall frequency of 5%and 2%,the debris flow in Xiaojiagou will cause partial siltation to the river,but it will not cause river blockage.However,it will cause river blockage under the condition of 1%rainfall frequency.

关 键 词：泥石流物源 遥感影像 FLO-2D 崩滑体 肖家沟泥石流 强震区 

分 类 号：P642[天文地球—工程地质学]